Or you can look at it from an optimistic-almost-narcissistic point of view and say that the interfaces that we have are so well-deaigned either by accident or o

Or you can look at it from an optimistic-almost-narcissistic point of view and say that the interfaces that we have are so well-deaigned either by accident or on purpose that the same level of accuracy can be achieved with whatever appendage. Personally, I think we stumbled onto a design that works well after years of trials. When you look at children using tablets, for example, you quickly realize that they don't have the same dexterity as adults, yet they are able to use the device with almost the same capability as adults. With tablets in particular, I don't think this was an accident... We could make input devices/interaction paradigms that are highly specific to one domain usable by only certain people because of learning curves or physical limitations, or input devices that can be used by anyone with sacrifice in speed and productivity.